Key Terms

Atom – The smallest particle of an element that possesses the unique characteristics of that element.
Barrier potential – The amount of energy required to produce full conduction across the pn junction in forward bias.
Conductor – A material that easily conducts electrical current.
Crystal – A solid material in which the atoms are arranged in a symmetrical pattern.
Doping – The process of imparting impurities to an intrinsic semiconductive material in order to control its conduction characteristics.
Electron – The basic particle of negative electrical charge.
Free electron – An electron that has acquired enough energy to break away from the valence band of the parent atom; also called a conduction electron.
Hole – The absence of an electron in the valence band of an atom.
Insulator – A material that does not normally conduct current.
Ionisation – The removal or addition of an electron from or to a neutral atom so that the resulting atom (called an ion) has a net positive or negative charge.
Orbital – Subshell in the quantum model of an atom.
PN junction – The boundary between two different types of semiconductive materials.
Proton –  The basic particle of positive charge.
Semiconductor – A material that lies between conductors and insulators in its conductive properties. Silicon, germanium, and carbon are examples.
Shell – An energy band in which electrons orbit the nucleus of an atom.
Silicon – A semiconductive material.
Valence – Related to the outer shell of an atom.